There are two references made to the Sabiuns in the Writings of Shoghi Effendi as one of the nine religions of the world.  According to historians, there are two groups associated with this name and this has been acknowledged in the Baha'i Writings.  This book is a research about those two groups to determine which one could be considered as one of the independent religions of the world.

Google:   The term "Sabiun" can refer to multiple groups, but most commonly refers to the followers of Mandaeism, a Gnostic, monotheistic religion that reveres John the Baptist as its final prophet. Historically, the term was also applied to other groups, including ancient Mesopotamian star worshippers or those with no fixed religion, but in modern usage in Iraq and Iran, it almost exclusively refers to the Mandaeans